Published on 5 March 2019 in The Proceedings of the National Academy of Sciences of the United States of America:
Molecular mechanism and history of non-sense to sense evolution of antifreeze glycoprotein gene in northern gadids
Xuan Zhuang, Chun Yang, Katherine R. Murphy, and C.-H. Christina Cheng
You can read the article here: https://www.pnas.org/content/116/10/4400
The authors show how an apparently irreduciblly complex phenotypical element arose by a combination of mutation and natural selection.